Field of the Invention
The present invention relates to an image projection apparatus and control method thereof.
Description of the Related Art
Conventionally, as a distortion correction method of an image projection apparatus, a technique for attaining distortion correction by deforming a projected image according to move instructions of points of four corners from the user is known. However, with this technique, since the points of the four corners cannot be moved outside the projected image, the user has to set the image projection apparatus before distortion correction so that the projected image includes a screen.
For example, Japanese Patent No. 4578341 and Japanese Patent Laid-Open No. 2006-121240 disclose the following technique. Initially, before distortion correction, a shooting is performed in a projecting direction by an image capturing unit to recognize a positional relationship between a projected region and projected image. Next, a zoom condition that the outer circumference of the projected image is not located within a screen region and the projected image becomes as small as possible is calculated, a zoom lens is driven to satisfy that condition, and the image is then deformed to attain distortion correction of the projected image.
However, the technique described in Japanese Patent No. 4578341 and Japanese Patent Laid-Open No. 2006-121240 requires the image capturing unit to recognize the projected region before distortion correction, resulting in an increase in cost. Also, when a projected region cannot be specified from a captured image (for example, when an image is projected onto a plain wall), distortion correction cannot be appropriately attained.